Two-blade shutter having built-in flash synchronizing switch



Jan. 9, 1951 $537,888

C. C. FUERST TWO-BLADE SHUTTER HAVING BUILT-IN FLASH SYNCHRONIZING SWITCH Filed Dec. 5, 1947 CARL C. F UERST IN T EN TOR BY 7, M A TORNEY Patented Jan. 9, 1951 'LUNIT ED l PATENT @OEFJIICTEY 0 IBLADE JS HUTTER "HAVIN G BUILT :IN

FLASH 'LSYNCHRONIZ'IN G SWITCH CarIiCI FIIBI'St; Rnchesten-N. Y.; assignor .to Eastmanz'Kodak :Gompany, Rochester, 5N Y.; :a col- 1 poratianof NewrJersey ApplicationDe-cemher 3, 1947, Serial Nc;"'l89;534

l he present invention relates to flash synehronizers; and particularly :to a flash synchroniizer built into: a photographic shutter-of 'the beg tween the lens type.

EJ-ne object of the present "invention toprovide a flash synchronizer WhiCh'fiS louilt into a photographic shutter ofathe between-the-lens type -and which synchronizer i is particularly de- -=s'igned"for use with a specific type or shutter "mechanism, so that the combination of the two I 'formsa very efi'icien-t flash F shutter.

Another object is to provide abuilt-in'ilash Another objec't is to provide a fiash' shutter wher'e'in the shutter comprises:a pluralitysof shutter blades whose 'movement is :controlled by -a 'driving pin "and which driving p'in constitutes one :o'f a pair of switch contacts controlling the flash circuit.

"The novel features that I consider characteristic o'f my invention are set forth with particulafity in' the "appended claim. The invention 'itself; however, both as to "its 'organization and its methods of operation, together with: additional obJ'ects' and advantages thereof, will best be understood fromthe following description when "read in connection with theaccompanyingdraw- =ings, inwhi'ch Fig. 1 is apartial plan View of :a photographic shutter with the .cover removed and showing a flash synchronizer constructed in accordance with a prefered embodiment of the present in-s vention.

In this figure the shutter parts are 'shown in their released, 01' untensioned, 5908itions Fig. '2 is a partial plan view, simflar-Ito'FignL but showingthe parts in'the position they assume; during the release of the shutter, and withthe shutter blades full open and just before they Fig.'3 is a sectional detail taken sbus'tantially 'on'line3-3 of Fig. 1; and.

'-Fig.--4 is a sectional detail taken substantially on line 4-4 of Fig. 1.

Like reference characters refer to correspondingparts throughout the drawings.

The present invention relates to the com'binatiOn of a flash synchronizerwith aparticulantype of between-the-lens; shutter shown wherein the movement of "the shutter blades is "controlled by; a "driving-pin between an operativeposition,i;wherein-the blades are open, and-an ilinoperativemosi- 1*.-

(clues-11.5)

tion, -wherein the blades are closed. "The'driving pin 'is normally spring-pressed "to its inoperative position and movedto its-operativeposition aiid then releasedbya cam on:a spring-drivenmaster ring during its movement from a -co'ckedposition.

The drivingpin for the blades constitutes 'one contact of a'fiash switch'in the shutter sothat synchronization can be efiicientlyobtained with little-diificulty and little added cost.

The shutter blade mechanismdisc'losed :is n-ot broadly new per se, a similar one being disclosed in mycopending US. patent'applic'ation serflqo.

712,349, filed iiovemberfifi, 1946; now PatentNo.

' 24-75952 issued July 12,1949, but the combination of the shutter blade mechanism with afiash synchronizer is new and is the'subject-df' the "present invention.

As indicated in Fig. 1, the present' fiash shutter'may' consist of a casing' l 'having' an upstanding flange 2 aroundtheperip'hery 'andian-expm sure aperture' iv in'the center of thecasing. "The fiange Zisslotted ate so that a 'shutter trigger E may project through the flange and inay move "from the latching position shown in Fig.' 1'tothe released position shown in Fig. "2. "Thetrigger *5' is pivoted on a stud-:6 'and a spring i norma'lly holds the trigger in its'latching'positiomas shown in-Fig. 1. Thetrigger also-may include aproje'ction 3 disposed in alignment with "the 'cable release bush 9' in the flange Y 2 so that theltrigger "may be operated through 'a :cable release shown 'in'part ate, ratherthan by a manual operation of the trigger fi.

"This shutter includes a 'pair of likeshutter "blades 1 B, each=pivoted atone end and to one-side 1 eithe -exposure apertureS on separate pins H :ex-

tending-downwardly from the mechanism-plate 12. Qverlapping-portions of'eachrof theshutter blades are provided with elongated slots P3 -fdisposed intermediately'pivot points i I of .t-hel-blades "and .the blades are caused to open and :olose-Lthe exposure-aperture by movement of a drivingpin I 4, engaging the slots l3, substantially-.radially -"ofthe casing-and between aninoperative position shown in Fig. '1 an operative position shown in Fig. 2. When the driving pin 14 is in its iinop- "*erative position v(see Fig." 1 ,orneare'stthe center of the casing the shutter blades are closed: iby

virtue'bfthe 'pin-and'-slot connection. Onirthe 1 i other hand, when the driving pin l' l 'iis imovediin the "direction indicated by '='the arrow in Figiz-tito "*i'tsoperative position (see Fig. 2) the bladesrare moved totheir full openposition.

In -my aboveenoted. :copendingipatentrabplieaitionfIihave shown-the equivalent:nil-thefidnivih pin M as being carried by one blade and passing through a slot in the other. While this arrangement is operative, I have found that some difflculty is encountered because of the thin gauge of the shutter blades to which the pin is fastened and a cooking of the pin occasioned by driving it in its two directions to separate the blades. Accordingly, in the present embodiment I mount the driving pin M on a lever pivoted to a stud l6 fixed to and extending above the mechanism plate i2. A spring I! wrapped around the stud l6, and anchored at one end against the flange 2 and at the other end to the edge of the lever, normally moves the lever in a counterclockwise direction. Thus, this spring normally acts to move the driving pin I4 to its inoperative position (see Fig. 1) wherein it closes the shutter blades.

The opening and closing movements of the shutter blades are controlled by a ring-shaped master member 2%]; this member turning about an upwardly extending flange 2| on the mechanism plate l2 in encirclz'u'igrelation with the exposure aperture 3, as clearly set forth in my above-noted patent application. A spring 22 attached at one end to a pin 23 carried by the master member and at the other end to a stud 24 carried by the mechanism plate normally holds the ring 2|] in its released or rest position shown in Fig. 1 with one side of the setting arm 25 thereon engaging a pin 25 fixed in the mechanism plate H. The master ring 2b is cooked by moving it in a clockwise direction by the use of the setting arm 25 extending through a slot 21 in the flange 2 against the action of sprin 22 until the end 28 of the trigger 5 drops in front of the latch member 29 extending from the periphery of the ring 20, as shown by the dotted line position of latch member 29 in Fig. 1.

When the master ring is moved to its cocked position, the blade-operating cam 38 extending from the periphery thereof assumes the dotted line position shown in Fig. 1. To permit this cam to pass over the end 3i of the lever I5 during the cocking operation of the shutter without causing said lever to be pivoted, the body of the cam is cut back, as indicated at 32, and the end of the cam is turned up, as clearly shown at 33 in Figs. 3 and 4. Thus, as the master ring is moved clockwise to its cocked position, the turned-up end 33 of the cam rides up over the lever and drops down on the other side thereof. This necessitates the master ring 2!} tilting slightly and this movement is permitted because of a pair of oppositely disposed spring clips 35'; each being attached to the mechanism plate l2 by means of a stud 36. Both of these clips are resilient and, while they tend to hold the master ring 20 flat in a plane upon the mechanism plate, nevertheless they allow the ring to move from this plane in a more or less axial direction so that the ring may rock from its plane when the cam 30 passes over the end 3| of lever l5 during cooking of the shutter.

The blade-operating cam so has an inclined cam surface 35 which is adapted to engage a corresponding inclined surface 36 on the end 3| of lever l5 when the master ring is moving counterclockwise under the action of spring 22 to pivot the lever and the blade-operatin pin l4 thereon in a direction to open the shutter blades. This cam surface 35 has a rise sufficient to cause the blades to be fully opened. During continued movement of the ring, the end 3| of lever I5 rides onto a cam surface 3'! contiguous with cam surface 35 and which is concentric with the exposure aperture. While the end 3! of lever I5 is in engagement with this cam surface, the blades are held in their full-open position, as shown in Fig. 2, and thereafter the cam moves out from under the lever and the lever drops back to its normal position under the action of spring ll, whereupon the shutter blades are closed. It will thus be seen that as the master ring 26 is moving from its cocked position under the action of driving spring 22, the blade-operating cam 30 moves the pin I 4 against the action of its spring causing the shutter blades to open; holds them open for a short time and then permits them to close to make the exposure.

Coming now to the flash synchronizer of the present invention, it is one which is adapted to accommodate that type of conventional flash lamp having a lag of approximately five milliseconds, or lamps of the gaseous discharge type which have no lag, but not flash lamps having the longer lags of twenty milliseconds. These two types of flash lamps, first mentioned, have lag characteristics which allow them to be synchronized with the shutter by closing the lamp circuit at substantially the instant the shutter reaches is full-open position.

According to the present invention, the flash lamp circuit is controlled by a pair of switch contacts, one of which is the shutter blade driving pin M, or, in reality, an extension thereof, while the other is a spring contact 43 disposed in the path of movement of the driving pin to be engaged thereby at substantially the instant the shutter blades reach their full-open position. Fixed to the flange 2 of the shutter is a conventional electric terminal T onto which a known type of electrical jack, not shown, is adapted to be slipped to connect one side of a circuit including a flash lamp L and source of current B to the shutter contacts in the shutter. The shell of the terminal T is grounded to the shutter casing so as to connect one side of the circuit to the shutter driving pin through the shutter mechanism. The insulated center post of the terminal T extends into the shutter casin and is equipped with a binding post P to which the sprin con-.

tact 40 is directly connected.

As clearly shown in 3 and i, the driving pin 14 has a extension M which extends upwardly from the lever l5 and constitutes the movable switch contact. This extension [4 is grooved, as shown at d5, to seat the spring contact 49 when engaged thereby and thus prevent the contact as from moving axially of extension l4 and slipping over the top thereof. It will be readily understood that by bending contact 40 at a point adjacent the binding post P, the end of the contact can be disposed relative to the driving pin i i and its extension Hi, so as to be engaged thereby in proper timed relation to the opening of t e shutter blades to secure synchronization.

From the above description it will be readily understood that the present combination of shutter and built-in. ilash synchronizer is achieved by the addition of a minimum number of parts to the shutter per se. in fact, all that is required is the terminal T, the contact 48, and an extension M on the shutter-driving pin. The combination makes possible easy initial adjustment and continued efiicient operation because it involves no movable parts separate from the shutter blade operating mechanism wherein lost motion may be involved, and contains no long electrical lead wires which require insulation. Furthermore, the switch being operated by the blade mechanism, its time of closing is independent of any manual control so that synchronization does not depend upon the speed at which the trigger is operated. In addition, the switch arrangement is such that the spring action thereof does not oppose or slow up the speed of operation of the master ring which controls the operation of the shutter blades.

Although I have shown and described certain specific arrangements of my invention, I am aware that many modifications thereof are possible. My invention therefore is not intended to be limited to the specific details of construction shown and described but is intended to cover all modifications coming within the scope of the appended claim.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

In a photographic shutter having a built-in flash synchronizer the combination of a circular casing provided with an exposure aperture; a pair of shutter blades pivoted in spaced relation on the same side of said aperture for opening and closing said aperture, and having overlapping portions each provided with an elongated slot disposed eccentrically of and intermediate the pivot points of said blades so that saidslots he one above the other; means for moving said blades between an open and aclosed position relative to said aperture, and including a driving pin extending through said elongated slots and mounted to move between a normal inoperative position, wherein it closes said blades, and an operative position, wherein it opens said blades; means for moving said driving pin between its two positions, including a spring-driven member movable between a cooked position and a released position, a cam on said driven member adapted to move said driving pin to its operative position and allow it to again return to its inoperative position when said driven member moves from its cocked position; a flash synchronizer circuit including a pair of switch contacts, one of said contacts being said driving pin, and the other contact being a stationary flexible member disposed in said casing in the path of movement of said driving pin to be engaged by said pin substantially at the instant when said pin reaches its operative position.

CARL C. FUERST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS i Number Name Date 2,129,561 Brueck Sept. 6, 1938 2,145,917 Boesser Feb. 7, 1939 2,196,604 Galter Apr. 9, 1940 2,198,975 Pollock Apr. 30, 1940 2,282,850 Brownscombe May 12, 1942 2,290,362 Springer July 21, 1942 2,340,405 Schwarz Feb. 1, 1944 2,356,455 Fuerst Aug. 22, 1944 

